docs(tabs): update examples

docs/app/components/content/examples/tabs/TabsSelectedExample.vue

@@ -9,6 +9,13 @@ const items = [
 ]
 
 const selected = ref('1')
+
+// Note: This is for demonstration purposes only.
+onMounted(() => {
+  setInterval(() => {
+    selected.value = selected.value === '0' ? '1' : '0'
+  }, 1000)
+})
 </script>
 
 <template>